Ratchet screwdriver is a screwdriver with a design of a switching turning drive device, which enables its joint to turn clockwise or anti-clockwise. This can make the screwdriver constantly positioned on bolts while screwing down or slackening bolts without repeating a turning operation. As for the structure of ratchet screwdriver, the turning drive switching device is usually positioned at the forepart of grip and the restraint joint is extended a fixed distance from the turning drive switching device. However, some shortcomings are learnt in its application. Since the joint distance of ratchet screwdriver is fixed, its application is limited under varied working environments.
Therefore, much is desired in the design of a retractable and convenient joint for a ratchet screwdriver.